Electric switch



Feb. 4, 1958 c. A. SCHAEFER ET AL ELECTRIC SWITCH 4 Sheets-Sheet 1 Filed Feb. 10, 1955 INVENTORS CARL. A. SCHAEFER RUDOLF H. Kaessune,

EARL F. MEN-.LBuRe BY Feb. 4, 1958 c. A. SCHAEFER ET AL 2,822,439

ELECTRIC SWITCH 4 Sheets-Sheet 3 Filed Feb. 10, 1955 1958 c. A. SCHAEFER- ET AL 2,822,439

ELECTRIC SWITCH INVENTORS CARL A. SCHREFER RUDOLF H. KIESSLJNG EARL F. MEKaLauRa ATT RNEY United S ates Patent ELECTRIC SWITCH Carl A. Schaefer, Whitefish Bay, Rudolf H. Kiessling, Milwaukee, and Earl F. Mekelbnrg, Wauwatosa, Wis., assignors to Square D Company, Detroit, Mich, a corporation of Michigan Application February 10, 1955, Serial No. 487,282

20 Claims. (Cl. 200-70) This invention concerns a novel type of switch and more particularly the type known as limit switches. Limit switches, actuated by moving machine elements, are ordinarily used as pilot devices in the control circuits of magnetic starters to govern starting, stopping or reversing of electric motors. Recently the advent of automation has increased the use of limit switches to the extent that myriad other applications are obvious and many more contemplated. Therefore, it has become necessary to provide many types and variations'of a standard limit switch, such as shown in the patent to H. L. Van Valken burg, Patent No. 2,352,815, to obtain the multiplicity of uses required. Also, in machine tool service, for example, it is necessary to provide limit switches which are characterized by quick make and break operation with its accompanying accuracy of tripping. It is obvious, then, that the need exists for a universal type limit switch with optional snap-action features which will obtain a multiplicity of switching functions without utilization of numerous additional parts or complicated mechanical changes. This can be further explained when it is realized that a normal application of a limit switch requires a certain type of operating mechanism to per form its particular function while another application will require a substantially altered limit switch to perform another particular function, which obviously requires a limit switch supplier to stock many different types, sizes, etc. Therefore, it is an object of this invention to provide a universal type limit switch which utilizes a basic switch mechanism having adjustable and substitute components and optional snap action that can be altered simply and readily to change the switch to accomplish a multiplicity of switching functions, without requiring many additional parts or complicated tools. In fact, in utilizing this invention only a screw driver is needed to perform many of the switch changes that are required, and parts may be added or subtracted to obtain many more switch changes. It is this versatility of the invention that permits a user to stock only the basic switch mechanism to have at his disposal a switch adaptable to many applications and uses. Obviously, it also enables the re-use of the same switch in a new or changed application by a simple alteration without the necessity of purchasing an entirely new switch.

It is a further object of this invention to provide a limit switch, as above, having a neutral or OFF position with snap action in either of two opposite directions to close opposite sets of contacts and return to neutral position. a

It is a still further object of this invention to provide a switch wherein normally closed contacts may be actuated to a second position by an actuating force moving in either a first direction and upon release thereof to return the contacts to their normal positions, or moving in an opposite direction to accomplish identical switching action and upon release thereof to return the contacts to their normal positions.

. These and further objects will be readily apparent to" those skilled in the art from the specification and appended drawings illustrating certain preferredembodiments in which:

Figure 1 is a rear elevational viewof the limit switch with. the back cover removed, and shown in one of its switch arrangements.

Figure 2 is a vertical sectional view taken on the line 11-11 of Figure 1.

Figure 3 is a front elevational view of the limit switch of Figure 1 with the front cover removed.

Figure 4 is a fragmentary rear elevational view of the limit switch shown in another of its switch arrangements and with portions removed for clarity.

Figure 5 is a horizontal sectional view taken on the line VV of Figure 1.

Figure 6 is a rear elevational view of a modified form of the limit switchof Figure 1.

Figure 7'-is a rear elevational. view of the limit switch of Figure 1, shown in another of its switch arrangements.

Figure 8 is-a rear elevational view of the. limit switch of Figure 1, shown in another of its switch arrangements.

Figure 9 is arear elevational view of the limit switch of Figure 1, shown in another of its switch arrangements. Figure 10 is a rearelevational view of the limit switch of Figure l, shown'in another of its switch arrangements. Figure 11 is a rear elevational view of the limit switch of Figure 1, illustrating the overtravel mechanism and .the position of. the operating-parts after actuation thereof. Figure 12 is a fragmentary front elevational view of the limit switch of Figure 1 and Figure'2 after actuation thereof. 7 Figure 13 is a diagrammatic illustration of'the different switching arrangements provided by this invention.

Figure 14 is a plan view of theo'perating cam of Figure 6.

Figure 15 is a plan view of the operating cam of Figures 1, 2, 3, 9, 10, 11 and 12.

Figure 16 is a side view of themovable contact member utilized in the switch mechanism of this invention.

In each of the several figures, including themodifications and switch combinations, identical reference characters indicate identical parts which may be interchange ably used, and reference characters with the sufiix M indicate substantially similar parts except as otherwise distinguished.

Referring now to Figures 1, 2, 3 and 5 in whichare shown details of the limit switch which will be first described in mechanical corelation irrespective of switch or component position. A substantially rectangular casing 2, open at the front and back, provides a'receptacle and supporting structure for the various switch elements. A supporting plate 4 and a cover 6 (Figure 2) seal off the back and front openings, respectively, of casing 16 and 13 mount the outer stationary contact of eachpair 12 and 14 in place upon the contact blockiand serve to secure the terminals of lead-in 'wires to the contact block 8. Similarly, long terminal fingers 20 and 22, that; extend downwardly (Figure 3) along the sides ofv theblock 8, mount the inner stationary contact of each pair. .12 and 14 in place upon contact block 8 and serve to secure the terminals of lead-in wires to the block. The

block 8 is secured to inner shelves on casing 2 by means;

of screws 3 and 5.

A movable contact member 24, disposed within the 2,822,489 I e e r opening 10, is pivotally mounted on a stud 26, fastened integrally to the casing 2 and internally threaded to contain screw 5. The contact member 24 comprises an insulating piece 28 to which is secured a contact assembly, a support bracket 32 and bushing 4lriveted thereto (Figures 2, 3 and 16). The contact assembly 30 comprises two oppositely disposed pairs of contacts 34 and 36 biased apart within a retaining bracket 38 by means of pin 48 journaled within a projection bearing integral with casing 2, is provided at one end with a pair of oppositely extending rollers 50 and 52, having a common pivot pin therethrough. The shorter roller 52 is interposed between the ends 44 and 45 of spring 42 and is adapted to move the contact member 24 about the stud 26. This arrangement also provides a strain relief connection for movement of the operating lever 45 and roller 52 beyond the fixed limits of travel of the contact member 24. These fixed limits of travel are determined by oppositely located abutments 53 and 59 on the casing 2, which prevent rotation of bracket 32 beyond such limits by engagement with the projections 47 and 49.

As illustrated in Figures 4 and 5, latching means for the switch are provided, and consist of a pair of latch assemblies 60 and 64 adapted for engagement with the projections 47 and 49 of bracket 32. A left hand latch assembly 6t), pivotally and removably mounted on a bearing post 62, has a two-step latch surface 61 and a one-step latch surface 63. A right hand latch assembly 64, pivotallyv and removably mounted on a bearing post 66, has a two-step latch surface 65 and a one-step latch surface 67. The latch assemblies 60 and 64 are similar except that their respective one-step and two-step latch surfaces are reversed. A spring 68 is secured to projections on the latch assemblies 60 and 64 and serves to bias the outer extremities toward each other. This arrangement provides a simple method of furnishing single or double step latch operation of the switch by permitting manual reversal of the latch assemblies on the bearing posts 62 and 66, i. e., latch assembly 60 replacing latch assembly 64 on post 66 and vice versa. As shown in Figure 4, the switch is in one-step latchposition with the latch assembly 60 on post 62 and latched in engagement with the left hand latch projection 47 of switch bracket 32. As shown in Figure l the switch is in two-step latch position with the latch assembly 60 on post 66 and in engagement with the right-hand latch projection 49 of switch bracket 32 and the latch assembly 64 on post 62 and in engagement with the left-hand latch projection 47 of switch bracket 32. The unlatching of each latch assembly is obtained by flat surfaces 51 and 53 of the operating lever 46 which are adapted to alternately engage the extremities of latch assemblies 64 and 60, respectively, when moved in the corresponding direction.

An upper extending portionof stud 26, concentric'with bushing 41, is adapted to receive a switch positioning means consisting in part of a position plate 57. A retaining screw 43 with its shank passing freely through the position plate 57 is threaded within the stud 26 and secures the position plate 57 in adjustable set position relative to the stud 26 and thereby the casing 2; while allowing relative movement thereto of the movable contact member 24 and its bushing 41 about the stud 26. The movement of contact member 24 relativeto the operatingflever 46 is restricted by the contact operating spring 42.' A return spring 39, concentrically disposed on an extended portion of position plate 57, has spring ends 69 and-'l0 biased 4 toward each other and projecting on either side of a bentover tongue 71 of position plate 57 and also extending along each side of the long roller 50 of operating lever 46. The spring 39 with its ends 69 and '70 serves a dual function: First, it provides a means for returning the operating lever 46 to a position determined by the preset position of plate 57 because it is movable with plate 57 and has its ends 69 and 70 in engagement with the roller 50 of lever 46; and secondly, it provides a means for initially positioning the operating lever 46 and consequently the movable switch member 24 as determined by the position of the semicircular slots A, O and B of position plate 57 in relation to posts 62 and 66. This latter function may be further explained when it is noted that the spring 39 is a stronger spring than contact operating spring 42 and is secured to the position plate 57 and movable therewith to force a position change on the operating lever 46 through its long roller 50 and because the short roller 52 is oppositely positioned from roller 50 and is engaged with the contact operating spring 42, thereby forces a change in position of the contact assembly 24. The semi-circular slots designated A, O and B of position plate 57 have oppositely disposed slots, which as a pair are adapted to engage reduced portions of posts 62 and 66. In Figures 7 and 8, the position plate 57 is shown in two of its three different positions, 0 and B corresponding to switch positions 0 and B, for varying the position relationship between the lever 46, the movable contact member 24, and latch projections 47 and 49, with respect to the one-step latch faces of latch assemblies 60 and 64. In Figures 1, 9 and 10, the mechanical effects of the three dilierent settings 0, A and B of the position plate 57 with respect to the operating lever 46, the movable contact member 24, latch projections 47 and 49 with respect to the operat- 57 may be accomplished by loosening screw 43, disengaging the slots from the ends of posts 62 and 66, twisting the plate 57 to the desired slot position and retightening screw 43. In Figure 6 a modified form of position plate 57M is shown, and only the slot A and its counterpart slot of the plate 5'7 are utilized. However, the parts shown below the pivot pin 48 would assume the same positions with either plate 57M or plate 57 in the A position, and this view is partially illustrative of both modifications.

The operating lever 46 of Figures 1, 3, 7, 9 and 11 has a pair of cam abutment rollers 54 and 56 at its opposite end, which are adapted to be alternately engaged by oppositely disposed lobes of an operating cam 25 to provide a pivotal actuating means for the operating lever 46. The cam 25 of a particular configuration (Figure 15) is rigidly secured to a shaft 27 pivoted within the casing 2. An overtravel spring 29, concentric with shaft 27, is interposed bctween the lower face of cam 25 and a boss on the casing 2. Ends 31 and 33 of spring 29 which are biased toward each other and extend on both sides of a turn-down tongue 73 of cam 25 are adapted to engage abutrnents 35 and 37, respectively, on the casing 2 in either direction of rotation of cam 25 and shaft 27. This arrangement permits the shaft 27 to rotate the cam 25 through an operating range in conjunction with the lever 46 and allow substantial overtravel beyond that range, with return to the initial operating position being effected by the spring 29, because of the tension exerted by either of the ends 31 and 33 against their respective abutment 35 or 73. In the modification shown in Figure 6, a cam 25M is provided which has a recessed portion or detent for engagement with a large abutment roller 72 on operating leyer 46M. Note that the lever 46M is a modified form of lever 46 with the roller 54 removed and large roller 72 substituted for roller 56, but in all other respects identical. On the outside of easing 2, to a projection of shaft 27, is affixed a hub 21 and roller arm 23 for providing an external operating means to veffect movement of cam 25. A roller 1:95on; roller arm zziprovides a relatively frictionless abutment for theapplicationof force to operate the switching mechanism inra; conventional limit switch application.

There are fourteen different switching functions or switch arrangements disclosed by this invention. 'As shown in Figure 13, tables-9 and '11 illustrate the various switch arrangements which may be provided by eifecting slight mechanical changes and with the position plate 57 and the latch assemblies 60 and 64in various combinations. The letters A, O and: B correspondto the settings of the position plate 57 and reflect switch positions as follows: A-switch A closed, i. e., contacts 34in engagement with contacts 12, neutral position of the switch (Figure 3), i. e., member 24 out of engagement with contacts 34 and 36, and B-switch B closed, i. e., contacts 36 in engagement with contacts 14. The table 9 of Figure 13 illustrates the switching combinations that are possible when the operating cam 25M, operating lever 46M, unipositional plate- 57M and roller 72 (Figure 6) are used with the basic switching mechanism in; either of three arrangements. One arrangement utilizes the onestep latches 61 and 65 in engagement with the projections 47 and 49. A second arrangement utilizes the two-step latches 63 and 67 in engagement withgthe projections 47 and 49. A third arrangement, with the latch assemblies 60 and 64 removed entirely, provides slow action or pilot duty without snapaction.

The. table 11 illustrates the switch combinations that are possible when the operating cam 25, operating lever 46 and tri-positional plate 57 are used with the basic switching mechanism in any of the three latch arrangements with four additional combinations provided bythe three positions of the position plate 57'and the omission of spring 39. In the diagrams of the table, the solid line indicates the position of the movable contact member 24 and its movable contacts 34 and 36 in relation-to the fixed contacts 12 (A) and 14 (B), prior to-movement of the actuating means, i. e., the roller arm 23, or after movement to a new permanent position which is not affected by the return of the roller arm 23 to its initial position. The dashed lines indicate transitory positions of the movable contact member 24 which are obtained when the roller arm is moved to a new position and upon release returns to its initial position with concurrent return of the contact member 24 to its previous solid line position. For example, with the two-step latches 60 and 64 injuxtaposition to the latch projections 47 and 49 respectively, and the position plate 57 placed in the 0 position (Figure 8) the movable contacts 34 and 36 will assume a neutral or mid-position out of engagement with both fixed contacts 12 (A) and 14 (B), as shown in Figure 3. This arrangement is shown diagrammatically in the lower table 11 of Figure 13, reading across the table from twostep to the diagram immediately below 0. In the diagram of the switching arrangement, one-step latches and O, the solid line indicates only the roller arm position, because here the switch may be quiescent in either A or B contact positions, depending upon the previous direction of travel of the roller arm 23.

Referring now. to Figures 1, 3, 11, 12 and 13, the operation of the limit switch with the adjustable mechanism in the positions shown, i. e., O positionof position plate 57 and two-step latch positions of latch assemblies 60 and 64 actively disposed, will now be described.

As heretofore mentioned, this setting of the position plate 57 and utilizing the two-step latches places the movable contact member 24 at its mid-position with the corresponding components as shown in Figures 1 and 3. With the advent of an external actuating force, such as the traveling bed of a machine tool, moving in a horizon? tal direction from left to right (Figures 3 and 12) and enga-gingthe roller 19 at its solid lineposition of Figures 1 and 3 and its dashed lineposition 19X. of Figures .11

' and 1 2.;th'e rollerarm 23 :moves ina clockwise direction ation.

The operation of the switch elements per se will now be described. With the initial force exerted on roller 19 and arm'23 in the clockwise direction (Figures 3 and 12) or counterclockwise direction (Figures 1 and 11), the cam 25 pivots counterclockwise from its position of Figure 1 until the right lobe moves the roller 56 and thereby moves operating lever 46. This action pivots the lever 46gclockwise around the pivot pin 48 to accomplish three functions: first, thelong roller 50 moves against the end 69 of return spring 39 to build up a spring return force for thelever 46; secondly, the short roller 52 moves against theend 44 of contact operating spring 42 to build up a snap action spring load for the movable contact member 24; and thirdly, the flat surface 51 of lever 46 abutting the end of latch assembly 64 engages the twostep latch 65 from the latchprojection47, working against the bias of spring 68, to allow'the movable contact member 2 4 to move witha snap action into engagement with fixed contacts l4 (B). Note that the projection 49 will rotate outof engagement with, the latch 61 because all the latchesare' unidirectionally engaged with each other.

-In this-arrangement the snap action is effected by the spring 42 and the latch engagement which releases only after the tension build-up of springs 29 and 42 has been eifected. After this action, the switch components are in the position shown in Figures 11 and 12, except that at this point of travel the roller arm 23 and roller 19 is in the position 19Y and the operating cam 25 in. the dashed lineposition 25Y. Further travel of the arm 23 in a counterclockwise direction (Figure 11) moves the cam 25 along the surface of roller 56 to the solid "line position of roller 19, arm 23 and 'camr25 to maintain the switch mechanism in its same relative position. Duning this over-travel operation the tongue 73 of cam 25 carries the end 31 of spring 29 to increase the spring tension, end 33 being retained by'abutment 37, to provide return force for the roller arm and cam assembly. After removal of the external actuating force, the spring 29 will thereby return the roller arm 23 and cam 25 to its approximate initial position and will allow return spring 39 and its end 69 to bring the switch mechanism back to its starting point and roller arm 23 to its exact initial position of Figure 1.

Similarly, horizontal movement of an actuating force from left to right (Figures 1 and 11) pivots the operating lever 46 counterclockwise to build up the spring force of springs 39 and 42 and. with the resultant disengagement of the two-step latch 61 from latch projection 49 moves the contact member 24 into engagement with fixed con tacts 12 (A). The return to neutral position is effected similarly to the previous operation.

In the operation of the switch as heretofore described; the overtravel spring 29 is not effective during the switching operation in either direction because the ends 31 and 33 are not in engagement with their respective abutments 35 and 37 until after the switch operation. It is only during overtravel of the arm 23 that the spring 29'is ef-, fective-to perform its function and the main return spring for the switch mechanism, including the operating lever 46,- is the spring 39.

The switch arrangement illustrated in the lowertable 11, the one-step latches and 0 position will now be .de scribed. This arrangement is accomplished byremoval of the screw 43 and plate 57, and reversing theclatch assemblies 60 and from their two-step latch positions A 7 to their one-step positions with subsequent replacement of .the plate 57 and screw 43 to the position. -The switch 'mechanism then will be in either switchA or switch B engagement depending upon'the preceding direction of travel of the roller arm 23. Assuming that switch B is closed corresponding to the component positions of Figures 8 and 12, except that in Figure 12 for this setting 1 the actual position of roller 19 will approximate the position 19X, movement of roller arm 23 in a clockwise direction will not efiect switch operation and the switch 'mechanism will remain in the position as shown. However, movement of roller arm 23 from position 19X counterclockwise (Figure 12) results in counterclockwise movement (Figure 8) of operating lever 46. The long roller 56 and short roller 52 engages the spring ends 70 and 45 respectively to build up the spring force of springs -39 and 42 and with subsequent disengagement of latch 67 from projection 49 moves the contact member 24 into engagement with fixed contacts 12 (A); In this switch position the components are as shown in Figure 4 and operation of the arm 23 in the reverse direction is required to return the switch mechanism, to its starting position.

The changeover to the switch arrangement, A position of plates 57, with the two-step latches actively disposed, accomplished by removal of screw 43 and plate 57, with reversing of latch assemblies 60 and 64, and the forcible pivoting of plate 57 to the A slots with subsequent re placement of screw 43, pivots the movable contact member 24 and contacts 34 into engagement with contacts 12 (A), and engages latch surface 65with latch projection 47 (Figure 9). In this setting, movement of the roller arm 23 counterclockwise about the pivot shaft 27, pivots the cam 25 counterclockwise against the roller 56, of lever 46 (Figure 9). In this setting, movement of the roller arm 23 counterclockwise about the pivot shaft 27, pivots the cam 25 counterclockwise against the roller 56 of lever 46 (Figure 9). This effects clockwise rotation of lever 46, first, to build up the tension of springs 39 and 42, and, secondly, to move latch assembly 64 and latch surface 65 slightly away from the projection 47 while simultaneously rotating the support bracket 32 and projections 47 and 49 to momentarily bring the lower step of each latch surfaces'65 and 61 into engagement with their corresponding projections 47 and 49, similar to the at-rest position of Figure 1. At this position of the operatingmechanisrn, the switch member 24 assumes its neutral or mid-position for as long as the roller arm 23 remains at this point in its travel. Continued rotation of arm 23 completes the switching action as follows: the surface 51 of lever 46 continuing in the clockwise direction disengages the lower step of latch 65 from projection 47, allowing further rotation of the switch member 24 into engagement with contact 14 (B) and the upper step of latch surface 61 into engagement with projection 4?, similarly to the starting position of Figure 10. Further movement of arm 23 in the same direction will constitute overtravel of the mechanism as heretofore described. Upon release of the arm 23 and roller 19'the switch mechanism snaps back to its startingpositiou (A) with a momentary hesitation at the mid-position. This setting is utilized where a mid-point or neutral switch position is required after breaking one set of contacts and before making another set of contacts.

Similarly, the switch arrangement with the B position of position plate 57 and the two-step latches as shown in Figures and 11 provide switch operation opposite to that of Figure 9, the A position and two-step latches arrangement.

The switch arrangement with the A position of position plate 57 and the one step latches actively disposed, provides switch operation similar to that setting, A position and two-step latches, but without the midpoint or neutral switch position. 1 P Also, the switch arrangement with the B position of position corresponding to the slots in the plate 57.

Note that in all the switch arrangements utilizing the position plate 57 the position change is accomplished by biasing the movable contact member 24 to a switch i In some arrangements, such as the 0 position and one-step latch arrangement, the latches will prevent the contact member 24 from assuming its normal set position but the bias toward that position is maintained regardless.

The switch arrangement with the one-step latches in juxtaposition to the projections 47 and 49 and the return spring 39 omitted, provides two position'maintained switching operation wherebytravel of arm 23 in one direction opens one set of contacts and closes another set, and as long as travel in this direction continues, or reverse travel is not efiected, the contacts last closed will bemaintained in their closed position. Heretofore, release of the arm 23 would eifect return operation to the starting position because of the presence of spring If reverse travel of arm 23 is initiated, the switching action is reversed to the original position of the components. This setting alsoprovides snap-action in both directions because of the combination of spring 42 and the latches.

Similarly, the switch arrangement with the two-step latches in juxtaposition to the projections 47 and 49, and the return spring 39 omitted,'provides a three position maintained switching operation, such as from A to '0, from O to B, from B to-O and from O to A, depending upon where the arm 23 stops and the direction it is moving. This arrangementv also provides snap-action between each of the switch positions 0, A, and B in either direction. H

Inthe switch arrangement illustrated in table9, Figure 13, i. e., the one-step latch position and utilizing the cam 25M, lever 46M and plate 57M, the mechanismwill assume the positions as shown in Figure 6. 'Then either clockwise or counterclockwise rotation of cam 25M rotates the roller 72 out of the declivity or detent of cam 25M to pivot the lever 46M in a clockmoves out of engagement with the switch A and into engagement with switch B. Upon release, the contact "arm 23 returns to its starting position under the influence of return spring 39 with the roller 72 retained within the declivity of cam 25M.

Similarly, in the switch arrangement illustrated in table 9, Figure 13, i. e., the two-step latch position and utilizing cam 25M, lever 46M and plate 57M, provides the midpoint or neutral position for the switch in addition to the arrangement heretofore described.

Also, in the third arrangement illustrated in table 9, i. e., with the latches omitted, the switch action will be sirnilar to the one-step latch position of table 9 but without snap action.

In the various uses for a switch of this type, many different applications require the use of roller arms and rollers of different shapes andsizes, therefore only a representative type is illustrated to indicate an actuating member for the limit switch of this invention.

Therefore, while certain preferred embodiments of this invention have been specifically disclosed, it is understood that the invention is not limited thereto, as many variations will be readily apparent to those skilled in the art and the invention is to be given its broadest possible interpretation within the terms of the following claims.

' What is claimed is:

1. In an electric switch, an enclosure, a stationary contact mounted within said enclosure, a movable con tact, a switch member supported within said enclosure and actuable to movesaid movable contact intoand out of engagement with said fixed contact, a pivot for said switch member, a pair of interchangeable latches pivotally mounted within said enclosure and adapted to engage alternately with said switch member to restrain the movement thereof, each of said latches having oppositely disposed latch surfaces of a predetermined configuration arranged for selective engagement with the switch member to selectively vary the operation thereof, means biasing said latches into engagement with said switch member, spring means operable to effect snap movement of saidswitch member when moving. out of engagement with one of said latches and into engagement with the other, and operating means movable within said enclosure and operable to engage said switch member and release one of said latches in one direction of travel to actuate said movable contact and operable to engage said-switch member and release the other of said latches in another direction of travel to actuate said movable contact:

2. In a switching mechanism, a casing, a pair ofoppositely disposed stationary contacts mounted within said casing, a movable contact, a switch member pivotally mounted within said casing and actuable to move said:

into engagement with said switch member, each of said= latches having oppositely disposed latch surfaces of predetermined configuration interchangeable to vary the operation thereof, and operating means movable in one direction of travel and adapted to engage said switch member and release one of said latches to movesaid movable contact into engagement with one of said stationary contacts and movable in another direction. of travel andadapted to engage said switch member and release the other of said latches to move said movable contact into engagement with the other of said stationary contacts.

3. In a switching mechanism, an enclosure, a stationary contact mounted within said enclosure, a movable contact, a switch member pivotally mounted within said enclosure and actuable to move said movable contact into and out of engagement with saidstationary contact, adjustable positioning means adaptable to vary the operating position of said switch member and said movable contact in relation to said stationary contact, a pair of interchangeable latches mounted within said enclosure and adapted to alternately engage said switch member to restrain movement thereof, means biasing said latches into engagement with said switch member, and operating'means movable within said enclosure and operable in one direction of travel to engage said switch member and release one of said latches to actuate said movable contact and operable in another direction of travel to engage said switch member and release the other of said latches to actuate said movable contact.

4. In a switching mechanism having a multiplicty of switch settings, a casing, a pair of stationary contacts mounted on opposite sides of said casing, a movable contact,.a switch member pivotally mounted within said casing and actuable to move said movable contact into and out of engagement with each of said stationary contacts, adjustable positioning means adjustably movable to vary the operating position of said switch member and said movable contact in relation to said stationary contacts, a pair of interchangeable latches adaptable to engage said switch member torestrain movement thereof, said latches in one position being adapted to restrain said switch member in two positions and when interchanged being adapted to restrain said switch member in three positions, and operating means movable within said casing and adapted to engage said switch member and releasesaid latches to actuatesaidmovable contact as predetermined by the set position ofthe positioning means and latches..

on, saidcasin g andhaving means. adapted for engagement withgsaidurecessed portion, to maintain engagement therewithini'one, positionof said cam, said lever adapted to engage; said switchmember to actuate said movable con- .tact out. of engagement with one of said stationary. contacts. and into engagement with the other of said stationary c ntaCIsup nmQvement of said cam. by said operating means to another positionwithsaid recessed portion out ofv engagement.. with said means.

6.. Ina-switchingmechanism, a casing, a pair of stationary contacts; mounted on opposite sides of said casing, amovable contact, a switch member pivotally mounted withinsaidcasing andactuable in one directon to move said movable. contact-from a first position out of engage ment with said stationary contacts into a second position inengagementwith one of said pair of stationary contacts and actuablein an. opposite direction to move said. movable. contact from said first position into a third position in engagement with the other of said pair of stationary contacts, positioning means on said casing biasing said switch member in said first position, latching means pivotally mounted on said. casing and engageable with said switch member to restrain movement thereof," and operating means pivotally mounted on said casing and engageable with, saidfswitch member to actuate said switch member ineitherldirection, said operating means including means for releasing said latching means to permit said switch member to move with a snap action from said; first position to said second or third positions.

7. In a switching mechanism, a casing, a pair of stationary contacts mounted on opposite sides of said casing, a movable contact, a switch member pivotallymounted within said casing and actuable in one direction to-rnoye saidmovable contact from a first position in engagement with'one of said stationary contacts into a second position inengagement with the other of said stationary contacts and actuable in another direction to move said movable contact from .said second position to said first; position, positioning means on said casing biasing said switch member towarda third position with said movable contact out of engagement with said stationary contacts, latching means-pivotally mounted on said casing and engageable with said, switch member. to restrain movement thereof, and operatingmeans pivotally mounted on said casing and engageable.withsaidswitch member to actuate said switch member vinieither direction, said operating means includingm'eans for releasing said latching means to permit. said switch member to move with a snap action between said first, secondand third positions.

8.. In a switching mechanism, a casing, a pair of, Sta.- tionary contacts. mounted on opposite sides of said casing, amovable contact, a switch member pivotally mounted withinsaid casing and actuable in onefdirection to move said movable, contact from a first position in engagement with one ofsaid stationary contacts into a second position inengagement;with theiother of said stationary contacts, positioning means biasing said switch member in said first position and, operating to return said switch member tosaid first'position after actuation to said second position, latching means. pivotally mounted on said casing and engageablewith: said. switch member to' restrain movementthereof, and operating means pivotally mounted on said casing and engageable with said switch memberto actuate said switcth member in said one direction only,

9. In a snap-action switching mechanism, a casing, a 3

pair of stationary contacts mounted on opposite sides of said casing, a movable contact, a switch member pivotally mounted within said casing and actuable in one direction to move said movable contact through three positions from a first position in engagement with one of said stationary contacts and actuable in the opposite direction to move said movable contact through said three positions from a third position in engagement with the other of said stationary contacts, the second position of said switch member maintaining said movable contact out of engagement with both said stationary contacts, latching means pivotally mounted on said casing and engageable with said switch member to restrain movement thereof, spring means associated with said switch member, and operating means pivotally mounted on said casing and engageable with said switch member and said spring means to initially load said spring means and subsequently actuate said switch member and said movable contact from one of said three positions to another of said three positions, said operating means including means for releasing said latching means to release said switch member, whereby said spring means moves said switch member with a snap action between said positions.

10. In a switching mechanism, a casing, a pair of stationary contacts mounted on opposite sides of said casing,

a movable contact, a switch member pivotally mounted within said casing and actuable in one direction to move said movable contact from a first position in engagement with one of said stationary contacts into a second position out of engagement with said stationary contacts and into a third position in engagement with the other of said stationary contacts, positioning means biasing said switch member in said first position and operating to return said switch member to said first position after actuation to said second and third positions, latching means pivotally mounted on said casing and engageable with said switch member in each of said positions to restrain movement there- 'of, and operating means pivotally mounted on said casing and engageable with said switch member to actuate said switch member in said one direction only, said operating means including means for releasing said latching means.

11. In a switching mechanism, a casing, a pair of stationary contacts mounted on opposite sides of said casing, a movable contact, a switch member pivotally mounted within said casing and actuable to move said movable contact out of engagement with one of said stationary contacts and into engagement with the other of said stationary contacts, latching means pivotally mounted within said casing and engageable with said switch member to restrain movement thereof, an operating cam pivotally mounted on said casing and having a recessed portion therein, operating means operable to move said cam in response to an external actuating force, an operating lever pivotally mounted on said casing and having means adapted for engagement with said recessed portion to maintain engagement therewith in one position of said cam, and unlatching means operable by said lever to disengage said latching means from said switch member after initial movement of said lever, said lever engaging said switch member to actuate said movable contact out of engagement with one of said stationary contacts and into engagement with the other of said stationary contacts upon movement of said cam by said operating means to another position with said recessed portion out of engagement with said means.

12. In a switching mechanism, a casing, a pair of stationary contacts mounted on opposite sides of said casing, a movable contact, a switch member pivotally mounted within said casing and actuable to move'said movable contact out of engagement with one of said stationary contacts and into engagement with the other of said sta- 12 tionary contacts, reversible latches adaptable to engage said switch member to restrainmovement thereof, said 'latches in one position adapted to restrain said switch member in two positions, and in reverse position adapted '5 'to restrain said switch member in three positions,-an operating cam pivotally mounted on said casing and having a recessed portion therein, operating means operable to move said cam in response to an external actuating force, 'an operating lever pivotally mounted on said casing and having means engaging said recessed portion to maintain engagement therewith in one position of said cam, and unlatching means operable by said lever to disengage said latching means from said switch member after initial :movement of said lever, said lever adapted to engage said switch member to actuate said movable contact out 'of engagement with one of said stationary contacts and into engagement with the other of said stationary contacts upon movement of said cam by said operating means 'to another position with said recessed portion out of engagement with said means.

13. In a switching mechanism, a casing, a pair of stationary contacts, a movable contact member pivotally mounted within said casing and actuable in one direction "to' move from a first position relative to said stationary contacts into a second position relative to said stationary contacts and actuable in another direction to move from said second position to said first position, positioning means on said casing biasing said movable contact member toward a third position relative to said stationary contacts, latching means pivotally mounted on said casing and engageable with said movable contact member to restrain movement thereof from at least said first and second positions, and operating means pivotally mounted on said casing and engageable with said movable contact member to actuate said movable contact member in either direction, said operating means including means for releasing said latching means to permit said movable contact member to move from said latched positions.

14. In a switching mechanism, a casing, a pair of stationary contacts, a movable contact member pivotally mounted within said casing and actuable in one direction to move from a first position relative to said sta- -tionary contacts into a second position relative to said stationary contacts and actuable in another direction to move from said second position to said first position, positioning means on said casing biasing said movable contact member toward said first position, latching means pivotally mounted on said casing and engageable with 'said movable contact member to restrain movement thereof from said first and second positions, and operating means pivotally mounted on said casing and. engageable with said movable contact member to actuate said movable contact member in either direction, said operating means including means for releasing said latching means to permit said movable contact member to move from either of said latched positions. l5 In a switching mechanism having a multiplicity of switch settings, a casing, a pair of stationary contacts mounted on opposite sides of said casing, a movable contact member pivotally mounted within said casing and actuable to move into and out of engagement with each of said stationary contacts, adjustable positioning means 'adjustably movable to vary the operating position of said movable contact member relative to said stationary contacts to provide a multiplicity of predetermined switch settings, and operating means movable within said casing and adapted to actuate said movable contact member from one of said predetermined switch settings to another. 16 In a switching mechanism having a multiplicty of switch arrangements, a casing, 21 pair of stationary contacts mounted on opposite sides of said casing, a movable 'contact 'member pivotally mounted within said casing and actuable to move into and out of engagement with each of said stationary contacts, adjustable positioning means adjustably movable to vary the initial operating position of said movable contact member in relation to said stationary contacts, said positioning means including a multiplicity of oppositely disposed slots for alternate engagement with fixed posts on said casing to obtain a multiplicity of initial positions and switch arrangements, and operating means movable within said casing to actuate said movable contact member from one of said predetermined positions to another.

17. In a switching mechanism, a casing, a pair of stationary contacts mounted in said casing, a movable contact member pivotally mounted within said casing and actuable to move into and out of engagement with said stationary contacts, adjustable positioning means on said casing adjustably movable to vary the initial position of said movable contact member in relation to said stationary contacts, an operating cam pivotally mounted on said casing and having oppositely disposed lobe portions, means operable to move said cam in either direction, and an operating lever pivotally mounted on said casing and having a first abutment means engaging one of said lobe portions during initial movement of said cam in one direction and having a second abutment means engaging the other of said lobe portions during initial movement of said cam in the opposite direction, said lever being adapted to actuate said movable contact member from a first position in relation to said stationary contact upon movement of said cam in one direction and to efiect opposite movement of said movable contact member upon movement of said cam in the opposite direction.

18. In a switching mechanism, a casing, a pair of stationary contacts mounted on opposite sides of said casing, a movable contact member pivotally mounted within said casing and actuable in one direction to move from a first position into engagement with one of said stationary contacts and in the opposite direction to a second position in engagement with the other of said stationary contacts, latching means including a pair of interchangeable latch members each pivotally mounted on said casing and engageable with said movable contact member to restrain movement thereof, spring means associated with said movable contact member, and operating means pivotally mounted on said casing for engagement with said movable contact member and said spring means to initially load said spring means and subsequently actuate said movable contact member from the first of said positions to the other positions, said operating means including means for releasing said latching means after movement of said operating means to load said spring means to eifect snap action between said positions.

19. In a switch mechanism of the character described, the combination comprising; a casing, a pair of stationary contacts mounted on opposite sides of the casing, a movable contact, a switch member pivotally mounted within the casing and arranged to move the movable contact from one position to at least two other positions, positioning means resiliently connected with the member arranged to normally position the switch member in any one of said positions, a pair of interchangeable latches arranged for maintaining said switch member in any one of said positions and operating means pivotally mounted on the casing and engageable with the switch member to actuate the switch member from any one of said positions to the other positions, said operating means including means for releasing said latching means to permit said switch member to move with a snap action between said positions.

20. In a switch mechanism of the character described, the combination comprising; a casing, a pair of stationary contacts mounted on opposite sides of the casing, a movable contact, a switch member pivotally mounted within the casing and arranged to move the movable contact, a pair of interchangeable latches carried by the casing engageable with the switch member to restrain movement thereof, an operating means pivotal on the casing in either direction from an at rest position and resiliently connected with the switch member and adapted to release the latches and actuate the switch member for moving the movable contact into and out of engagement with the stationary contacts, and positioning means carried by the housing and resiliently connected to the operating means for constantly urging the operating means toward the at rest positions, said position means including; a member carried by the housing and a coiled spring having its ends arranged to simultaneously engage the member and operating means.

References Cited in the file of this patent UNITED STATES PATENTS 2,352,815 Van Valkenburg July 4, 1944 2,459,077 Jeflrey Jan. 11, 1949 FOREIGN PATENTS 553,917 Great Britain June 10, 1943 650,761 Germany Sept. 30, 1937 

